Reduction of vacuum-tube capacitance



Jan. 8, 1929.

A. MEISSNER REDUCT ION 0F VACUUMIUBE CAPACITANCE Filed Jan. 25, 1927 SM/Ill Z'ONDENSER 0f 0R0R 0F AMEN/TUBE 0/ 71/85 CIVIC/MIKE INVENTOR ALEXANDER mnssusa 8Y9 M add/ 4 ORNEY Patented Jan. 8, l929.

wire

DRAHTLOSE TELEGRAPHIE M. 3. BL, OF BERLIN, GERMANY, CORPORATION GERMANY.

iannncrron or vacuum-T BE caracrrancn Application filed January 25, 1927, Serial No. 163,326, and in Germany February 2, 1926.

This invention relatesto the reduction of vacuum tube capacitance and more particularly to a method and means-for accomplishing this by arranging a plurality of tri-elec trode units in series. r

The specification is accompanied by a drawing in which Figure l is a wiring diagram of one modification of my invention; and

Figure 2 is a wiring diagram of amore advanced modification in which the anode circuits, with relation to the direct current,

are arranged in parallel.

It is a well-known fact that in the use of transmitters and receivers for very short electromagnetic waves, the self-capacitance of the tube plays an important part. The generation of extra-short waves may be 1811 dered impossible on account of the fact that the electrode capacitance possesses such a high value that unduly large displacement currents are caused to flow across the tube.

Now, in accordance with the invention, in

arrangements for short waves, two or more tubes are to be connected in series, so thatworking potentials may be avoided, to use for such an arrangement as hereinbefore stated tubes having high emissivity and low plate potential.

But there are also chances of using circuit arrangements in which one and the same potential source is employed for the feeding of all of the tubes. This is shown, for example, in Fig. 2. It is, of course, necessary in these connections or circuit arrangements to separate the different circuits from each other as regards the flow of direct current and radio frequency currents by the addition of conveniently proportioned choke coils and block condensers. There further arises this danger that undesirable grounds may be created for radio frequency current owing to capacitive influences, a circumstance that should be particularly kept in mind with relower tube.

gard to the heatsupply battery. It istherefore recommendable to insert small choke:

coils in the heating-current leads in order to;

' thus prevent grounding through the heating batteryof the radio frequency currents.

For a better understanding of the idea the plate of tube R and the cathode or filament of tube R is a working oscillation circuit S. connected with each other through the condenser. 0. This shouldbe of high reactance, preferably of the order of magnitude of the tube capacitance, in order not to by-pass the V The control potential for the grids is produced by means of coupling an oscillation circuit 3 interposed between the grid and the filament of tube R with the' are inserted in the heating circuit. Of course,

a great number of different arrangements are conceivable in which the'basic features of the present invention may beincorporated. v

It is obvious that the invention is not llmited to the use of only two tubes in series, and furthermore, that the tri-electrode units need not each be incased in a separate evacuated envelope.

I claim:

1. In combination, vacuum tube circuits, a plurality of electrode units each comprising an anode, a cathode, and a control electrode, of which, relative to the path of alternating energy, the anode cathode electrodes are connected in series, and the control electrodes are connected in parallel, and areactance of the order of magnitude of the tube capacitance connected between the control electrodes. I

2. The combination with vacuum tube circuits, of a plurality of electrode units each comprising an anode, a cathode, and a control electrode, the anode and cathode electrodes of which are connected in series for high frequency currents, while relative to the path of direct energy, the anode and cathode electrodes are connected in parallel.

The grids of the two tubes are 3. In combination, a plurality of electrode units each comprising an anode, a cathode, and a control electrode, a source of energy, means including choke coils connecting said source to anode andcathode electrodes, means including blocking condensers connecting the anode and'cathode electrodes in series, an output circuit coupled'across the extreme anode and cathode of the series of electrode units,

and a circuit arranged to influence the control electrodes. i

4. In combination, a plurality of electrode units each comprising an-anode, a cathode,

and a control electrode, a sourceof anode current, means including choke coils connecting electrodes in series, an output circuit coupled across the extreme anode and cathode of the series of elect-rode units, and a circuit arranged to influence the control electrodes in arallel. e

5. In combination, a plurality of electrode units each comprising an anode, a. cathode, and a control electrode, means coupling the anode and cathode electrodes in series for alternating energy, an output circuit coupled across the extreme anode and cathode of the series of electrode units, a 0011 regeneratively control electrodes. a

ALEXANDER MEISSNER; 

